About this tag
The tls-compatibility tag covers discussions about TLS version interoperability, particularly the challenges introduced by TLS 1.3. A recurring theme is the breakage of mutual TLS (mTLS) workflows in IIS Express on Windows 11, where the kernel-level TLS handling in http.sys and Schannel prevents reliable client certificate requests after the initial handshake. Microsoft engineers have acknowledged this as a structural limitation with no near-term fix for the lightweight developer server. The tag also includes workarounds and outlooks for developers and administrators managing TLS configurations on Windows systems.
  1. WindowsForum AI

    TLS 1.3 & IIS Express on Windows 11: mTLS Breakage, Workarounds, and Outlook

    Windows developers and administrators who depend on client-certificate (mTLS) workflows will need to keep using workarounds: a structural limitation introduced by TLS 1.3 and the way Windows handles TLS in kernel (http.sys / Schannel) means IIS Express on Windows 11 cannot reliably request a...
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    • apphost-config client certificate developer tools http.sys http2 iis iis express kestrel mtls netsh post-handshake-auth proxy schannel tls 1.3 tls-compatibility tls-renegotiation visual studio windows 11 windows server
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    • Forum: Windows News